package com.tedu.sp06.fb;

import cn.tedu.web.util.JsonResult;
import org.springframework.cloud.netflix.zuul.filters.route.FallbackProvider;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.client.ClientHttpResponse;
import org.springframework.stereotype.Component;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.StandardCharsets;

/*
 调用商品服务失败时,执行这里的降级代码,返回降级结果
 */
@Component
public class ItemFB implements FallbackProvider {
    /*
        针对哪个后台服务调用失败,应用当前降级类
        返回值:
            "item-service" 只针对商品服务降级
            "*"    对所有后台服务,都应用当前降级类
            null     对所有后台服务,都应用当前降级类
     */
    @Override
    public String getRoute() {
        return "item-service";
    }

    /*
        返回给客户端的降级响应数据
        封装到response对象
     */
    @Override
    public ClientHttpResponse fallbackResponse(String route, Throwable cause) {

        return new ClientHttpResponse() {
            @Override
            public HttpStatus getStatusCode() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR;
            }

            @Override
            public int getRawStatusCode() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR.value();
            }

            @Override
            public String getStatusText() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR.getReasonPhrase();
            }

            @Override
            public void close() {
                //用来关闭下面的流
                //BAIS内存数组流,不占底层系统资源, 不需要关闭
                //文件流,占用系统文件资源
                //网络流.占用网络资源
                //数据库流,占用数据库资源
            }

            @Override
            public InputStream getBody() throws IOException {
                //JsonResult -->{code:500,msg:调用后台服务出错,data:null}
                String json = JsonResult
                        .err()
                        .code(500)
                        .msg("调用后台服务出错")
                        .toString();
                //将json封装到BAIS
                return new ByteArrayInputStream(json.getBytes("UTF-8"));
            }

            @Override
            public HttpHeaders getHeaders() {
                // Content-Type : application/json;charset=UTF-8
                HttpHeaders h = new HttpHeaders();
                h.set("Content-Type", "application/json;charset=UTF-8");
                return h;
            }
        };
    }
}
